The £14bn “Aecom canal” proposal for a north-south waterway to solve drought and water supply problems has been rebranded as The Natural Grid – and is seeking the involvement and support of other consultants in the sector.
David Weight, the Aecom associate director behind the idea of a canal from the water-rich Scottish borders or Northumbria to the south east, will discuss progress on the scheme at the Engineering Club at London’s Building Centre on 20 November.
Weight, now retired but still working as a consultant to Aecom, told CM that the last 18 months had been spent discussing the idea’s viability with the water companies, the Environment Agency, freight companies, and the Chartered Institute of Water and Environmental Management.
This work included an economic appraisal that judged the cost benefit ratio to be 1.8:1 benefits to costs in terms of improving water supply and guarding against future drought, but excluding the additional benefits of regeneration, freight transport, providing a route for High Voltage Direct Current cables, and leisure use on the canal.
Weight told CM: “We’ve done a study on the cost options of various routes, so we’re pretty confident it can be done. We calculated for extra costs in urban areas, and when the canal goes below a certain depth we budgeted for tunnels, and above a certain height for aqueducts. So we try to avoid all those, while keeping the route fairly direct.
The new plans are for a narrower canal rather than wider continental canals
“The counterfactual option [of not building the canal] involves building more reservoirs, routes between river valleys, possibly even desalination plants, and measures to cut water consumption. But the existing plans run out of steam by the 2030s, while we’re dealing with substantial population growth in the south east.
“Meanwhile, the water companies are also finding that their abstraction rights are often not being renewed by the Environment Agency, which puts a squeeze on the water companies. And while no one knows what’s happening with climate change, the risk of drought has to be greater in the future.”
He added that better water supply and irrigation could boost UK food production in the future, reducing our dependence on importing food from other parts of the world – which may themselves be subject to increased drought in the future.
But one change to the proposals floated 18 months ago is that the canal is now seen as being 10-15m wide – broadly similar to many of the UK canals existing today – rather than the 24m continental-style waterway originally discussed.
Weight explained: “We don’t want a waterway that would intimidate smaller craft – we want it to be desirable and not too industrial. Ten metres would be adequate in terms of water supply – we know that’s possible and pretty economic.”
Referring ahead to the Engineering Club event, he said: “On Thursday, I’ll be saying we want to work with others. We shouldn’t think of it as the Aecom canal, we’re happy with to work with Mott Macdonald, Arup, Atkins – maybe they have specialists that can help.”
The idea was first mooted last year
This is of course not a new idea. It is very similar to the well-known Grand Contour Canal proposal put forward by J F Pownall in 1943.
I think is a route we should consider seriously. I have thought for a long time how under used our canals are.There are probably numerous benefits – tourism, water supply and transport.